The present invention relates generally to apparatus for providing current to an electronic circuit housing, and more particularly to providing high currents to an integrated circuit package through a clamp, and methods of manufacturing a clamp and an electronic assembly, which includes a clamp.
Electronic circuits, and particularly computer and instrumentation circuits, have in recent years become increasingly powerful and fast. As these circuits become faster, and the currents they require also continue to increase. In some cases, integrated circuits (ICs) are requiring currents of up to 100 amps, and future ICs will likely require substantially more current.
Using prior art technologies, current is supplied to the IC""s package through connectors (e.g., pins, solder balls, etc.) located on the bottom surface of the package. FIG. 1 illustrates a cross-section of an electronic assembly in which power is supplied and returned through pins, in accordance with the prior art. The assembly includes IC 102, IC package 104, socket 106, and PC board 108.
IC 102 contains one or more circuits, which require current to operate. IC 102 is electrically and mechanically connected to the top surface of IC package 104, typically using wire-bond (not shown) or solder connections 112.
IC package 104, in turn, is electrically and mechanically coupled to the top surface of socket 106 using bottom connectors, such as pins 114, which mate with complementary pin holes within socket 106. Alternatively, IC package 104 could be coupled to socket 106 using solder connections, such as land grid array (LGA) or ball grid array (BGA) connections, for example. Connectors 114 are used to supply and return current to and from IC package 104, and also to carry input/output (I/O) signals to and from the package 104.
PC board 108 could be, for example, a motherboard of a computer or other electronic system. As such, it acts as a vehicle to supply power, ground, and I/O signals to integrated circuit 102. These power, ground, and other signals are supplied through traces or planes (not shown) on or within PC board 108, socket 106, connectors 114, and IC package 104.
Often, a large number of the package""s connectors (e.g., pins 114) are dedicated to supplying and returning current. For example, a typical package may have 300 of 500 connectors dedicated to current supply and return, leaving only about 200 connectors for I/O signals. The current carrying capacity of the package is limited by the cumulative cross sectional area of the current carrying connectors (e.g., the cross sectional area of the current carrying pins). If the current becomes too high, some or all of the current carrying connectors may permanently fail, resulting in a partial or full loss of IC functionality.
One prior art solution to the need for more power is to increase the number of connectors dedicated to power delivery. However, this solution further limits the number of connectors that can be dedicated to I/O signals. In order to provide more connectors for power and/or I/O signals, the connector count must be increased, thus increasing the package size. Package size increases typically are undesirable in most applications, because larger packages reduce IC device speeds due to increased inductance, and because of the consumer-driven trend within industry is to reduce the size of electronic systems.
In some cases, power is supplied to a package from a power pod, through an edge connector of an interposer (i.e., a substrate that provides a dimensional interface between connectors on a package and connectors on a socket or printed circuit board) upon which the package is mounted. A power pod is an additional power supply that typically supplies power to one device within a system, as opposed to supplying power to the entire system. That power is transmitted from the interposer to the package through the package""s bottom connectors. FIG. 2 illustrates a cross-section of an electronic assembly in which power is supplied and returned through a power pod connector 202, in accordance with the prior art. The assembly illustrated in FIG. 2 is similar to the assembly illustrated in FIG. 1, except that the IC package 204 is electrically and mechanically connected to an interposer 206, which in turn connects to a socket 208 mounted on PC board 210.
The power pod connector 202 can be a clamp with conductive surfaces 212, 214 on the insides of two opposing jaws 216. When engaged with the interposer 206, the conductive surface 212 on one jaw makes contact with a conductive plane 218 on the top surface of the interposer 206, while the conductive surface 214 on the opposing jaw makes contact with another conductive plane 220 on the bottom surface of the interposer 206. One conductive plane supplies current, while the other conductive plane returns current. This current travels from the conductive planes through vias and conductive layers within interposer 206, to the package""s connectors 222.
Although higher currents can be supplied using a power pod, the current must still travel from the interposer through the package""s connectors 222. Thus, the supplied current is relatively far from the IC, and the amount of current supplied to the package 204 is still limited by the cumulative cross sectional area of those connectors (e.g., pins 222), which are dedicated to power delivery. In addition, the conductive surfaces of a typical power pod connector do not connect to the interposer""s conductive planes with a high normal force. Accordingly, a non-negligible contact resistance is associated with the power pod, resulting in the power pod connector consuming a certain portion of the supplied power.
As the power requirements for ICs continue to increase, there is a need for power delivery apparatus that can supply higher currents than are possible using prior art technologies. In addition, what is needed is a power delivery apparatus that enables more package connectors to be dedicated to I/O signals, rather than to power supply and return, without increasing the package size. Further needed is a power delivery apparatus that supplies current closer to the IC and with a lower contact resistance than is possible using prior art, power pod connector solutions.